<div class="col-xs-0 col-sm-2 col-md-4"></div>
          <div class="col-xs-12 col-sm-8 col-md-4">
            <div class="panel panel-primary" id="login">
              <div class="panel-heading text-center">
                <h3 class="panel-title">Đăng nhập</h3>
              </div>
              <div class="panel-body">
                    <form class="form-horizontal" method="post" onsubmit="return validateForm()" role="form">
                      <div class="form-group">
                        <label for="inputEmail3" class="col-sm-4 control-label">Tài Khoản</label>
                        <div class="col-sm-8">
                          <input type="text" class="form-control" name="username" placeholder="">
                        </div>
                      </div>
                      <div class="form-group">
                        <label for="inputPassword3" class="col-sm-4 control-label">Mật Khẩu</label>
                        <div class="col-sm-8">
                          <input type="password" class="form-control" name="password" placeholder="">
                        </div>
                      </div>
                      <div class="form-group">
                        <div class="col-sm-offset-2 col-sm-10">
                          <button type="submit" class="btn btn-default">Đăng Nhập</button>
                        </div>
                      </div>
                    </form>
              </div>
            </div>
          </div>
<div class="col-xs-0 col-sm-2 col-md-4"></div>